Polyvinyl halides plasticized with (1&#39;, 2&#39;-dicarboxyethyl) undecylenates



Patented Jan. 1, 1952 POLYVINYL HALIDES PLASTICIZED WITH (1',2'DICARBOXYETHYL) U N D E CYL- ENATES Joachim Dazzi, Dayton, Ohio,assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation ofDelaware No Drawing. Application May 25, 1950, Serial No. 164,306

7 Claims.

This invention relates to compositions comprising polymers of vinylhalides and relates more particularly to compositions comprising vinylchloride polymers plasticized with esters of (1,2'- dicarboxyethyl)undecylenic acid.

A wide variety of plasticizers has been employed for the purpose ofimproving the physical properties of vinyl chloride polymers. Particularattention has been given to the improvement of flexibility and heat andlight stability of such plasticized compositions; .In many instances theimprovement in flexibility has been obtainable only .by sacrificingother desirable properties of an ideal polyvinyl chloride composition,such as low volatility, color and heat stability, water absorption, etc.

Now I have found that very good flexibility, without sacrifice oftemperature stability and low volatility, is imparted to vinyl chloridepolymers when there are employed with the polymers certain aralkylesters of (l',2-dicarboxyethyl)-undecylenic acid. Esters of this typeare broadly disclosed in the Clocker Patent U. S. No. 2,188,888.Briefly, they are obtainable by the addition reaction of maleicanhydride with oleic acid or its esters and subsequent esterification ofthe free hydroxy groups. While isomeric products are possible, and theposition at which the anhydride residue is attached to the undecyleniccompound is not known the reaction of undecylenic acid or of an alkylundecylenate with maleic anhydride proceeds probably according to thescheme:

wherein R. is a member of the group consisting of hydrogen, alkylradicals of from 1 to 4 carbon atoms and saturated aralkyl radicals offrom 7 to 8 carbon atoms.

Esterification of the resulting adduct with a saturated aralkyl alcoholof from 7 to 8 carbon atoms, e. g., benzyl alcohol, ,B-phenylethanol orp-, or m-rnethylbenzyl alcohol yields the tria-lkyl ester which probablyhas the structure:

CH2CH:(IH((llimfllld00R H-COOR' H:-COOR' in which R is as defined aboveand R is a satu- 2 rated aralkyl radical of from '7 to 8 carbon atoms.

Because of uncertainty concerning the position at which the maleicresidue is attached to the undecylenic group, the present esters will behereinafter referred to without stipulating the position of the(1,2-dicarboxyethyl) group.

As examples of compounds having the above general formula may bementioned tribenzyl (1',2' dicarboxyethyl)undecylenate, the alkyl 1,2'-bis (carbobenzyloxy) ethyl] undecylenates in which the alkyl grouphas from 1 to 4 carbon atoms, tris(phenethyl)(1',2-dicarboxyethyl)undecylenate, the alkyl[1',2-bis(carbophenethyloxy) ethyllundecylenates in which the alkylgroup has from 1 to 4 carbon atoms, the tris(methylbenzyl) (1',2'-dicarboxyethyl) undecylenates such as the tris (p-methylbenzyl)(l,2'-dicarboxyethyDundecylenates and the alkyl [1'.2-bis-(carbo-ar-methylbenzyl) ethyl] undecylenates in which the alkyl grouphas from 1 to 4 carbon atoms, e. g., butyl[1',2'-bis(carbo-p-methylbenzyl) ethyl] undecylenate.

I have found that in order to obtain stable,

light-colored adducts certain reaction conditions must be adhered tocarefully. For example, while the addition of maleic anhydride toundecylenic acid takes place under varying reaction conditions, usefulplasticizers for the present purpose are best prepared by conducting thereaction for comparatively short periods of time, say, from one hour to8 hours, at relatively low tempera tures, i. e., at temperatures notexceeding the decomposition point of the initial reactants. I have foundalso that great care should be used in isolating the desired products.After the esterification, I preferably fractionate the crude reactionmixture under a very low vacuum 1. e., at vacuums of 1 mm. of mercury orless. Fractionation at such low pressures minimizes the formation ofdark colored impurities whose presence in the finished product leads topoor plasticized compositions. Dark colored impurities are also avoidedby preparing the present (1',2 -ciicarboxyethyl) undecylenates accordingto the procedure described in my copending application, Serial No.144,393, filed February l5, 19507 The present aralkyl(1',2'-dicarboxyethyl undecylenates are valuable plasticizers forpolyvinyl chloride and copolymers of at least '70 per cent by weight ofvinyl chloride and up to 30 per cent by weight of an unsaturated monomercopolymerized therewith, for example vinyl acetate, vinylidene chloride,etc.

Adducts of acyclic olefinic acids and longchained unsaturated acids havebeen hitherto generally suggested for use as softening agents. I havenow found, however, that aralkyl (1',2'- dicarboalkoxy) undecylenates inwhich the aralkyl radicals have from '7 to 8 carbon atoms are ofoutstanding value as plasticizers, these esters serving not only tosoften vinyl chloride polymers, but also to impart simultaneously a highdegree of low temperature flexibility, very good temperature stabilityand great mechanical strength to these polymers. While many of theesters encompassed by the Clocker patent referred to above areincompatible with polymers and copolymers of' vinyl chloride and do notgive continuous, homogeneous compositions, esters of(1',2-dicarboxyethyl)undecylenic acid with aralkyl alcohols of from '7to 8 carbon atoms are compatible with vinyl chloride polymers and showno exudation of plasticizer even at plasticizer content of up to 50 percent. Although the quan tity of plasticizer will depend upon theparticular polymer to be plasticized and upon its molecular weight, it'is generally found that compositions having from per cent to 50 per centby weight of plasticizer will, in most cases, be satisfactory forgeneral utility. The good flexibility of the plasticized compositionsincreases with increasing plasticizer concentration.

In evaluating plasticizer efliciency use is made of the followingempirical testing procedures:

Compatibility.-Visual inspection of the plasticized composition isemployed, incompatibility of the plasticizer with the polymer beingdemon trated by cloudiness and exudation of the plasticizer. Y

Hardness.A standard instrument made by the Shore Instrument Company isused for this determination and expresses the hardness in units from 1to 100. The hardness of a composition is judged by its resistance to thepenetration of a standard needle applied to the composition under astandard load for a standard length of time.

Low temperature flexibility.-I .ow temperature flexibility is one of themost important properties of elastomeric vinyl compositions. While manyplasticizers will produce flexible compositions at room temperature theflexibility of these compositions at low temperatures may varyconsiderably, i. e. plasticized polyvinyl chloride compositions that areflexible at room temperature often become very brittle and useless atlow temperatures. Low temperature flexibility tests herein employed areaccording to the Clash-Berg method. This method determines the torsionalflexibility of a plastic at various temperatures. The temperature atwhich the vinyl composition exhibits an arbitrarily established minimumflexibility is defined as the low temperature flexibility of thecomposition. This value may also be defined as the lower temperaturelimit of the plasticized composition's usefulness as an elastomer.

Volatility-Just as a decrease in low temperatureoften results indecreased flexibility of a plasticized polymer composition so does adecrease in plasticizer concentration when caused byvolatilization ofthe plasticizer. Hence, plasticizers which are readily volatilized fromthe plasticized composition as a result of aging or heating areinefficient because upon volatilization the plasticized compositionsbecome stiff and hard. The test for plasticizer volatility hereinemployed is that described by the American Society for Testing Materialsunder the designation D-744-44T.

The invention is further illustrated, but not limited, by the followingexample:

Example Sixty parts of polyvinyl chloride and 40 parts by weight of thetribenzyl ester of (1f,2'-dicarboxyethyllundecylenic acid are mixed on arolling mill to a homogeneous blend. During the milling there wasobserved substantially no fuming and discoloration. A molded sheet ofthe mixture was clear and transparent and substantially colorless.Testing of the molded sheet for low temperature flexibility, accordingto the testing procedure described above, gave a value of minus 16 C.,which value denotes extremely good low temperature properties. Tests onthe volatility characteristics of the plasticized composition gave avalue of 2.0 per cent which showed very good retention of plasticizerand indicated good temperature characteristics of the composition. Theplasticized material had a hardness of 82 before the volatility test anda hardness of 82 after the volatility test. When subjected to heat at atemperature of 325 F. for a period of 30 minutes the clarity and colorof the molded product were substantially unchanged.

Instead of the ester employed in the example above, other aralkyl estersof (1',2-dicarboxyethyllundecylenio acid with saturated aralkyl alcoholsof from 7 to 8 carbon atoms give similarly valuable plasticizedpolyvinyl chloride compositions. Thus, by employing 40 parts by weightof the tris (phenethyl), or the tris(omethylbenzyl) ester of(l',2'-dicarboxyethyl)- undecylenic acid or ethyl[1',2-bis(carbobenzyloxy)ethyl]undecylenate with 60 parts by weight ofpolyvinyl chloride, or with 60 parts by weight of a vinyl chloride-vinylacetate copolymer known to the trade as Vinylite, there are obtainedclear, colorless compositions of very good flexibility and stability.

While the above example shows only compositions in which the ratio ofplasticizer to polymer content is 40:60, this ratio being employed inorder to get comparable eiflciencies, the content of ester to polyvinylchloride may be widely varied, depending upon the properties desired inthe final product. For many purposes a plasticizer content of, say, fromonly 10 per cent to 30 per cent is preferred. The'present esters arecompatible with polyvinyl chloride over wide ranges of concentrations,up to 50 per cent of esters based on the total weight of the plasticizedcomposition yielding desirable products.

Although the invention has been described particularly with reference tothe use of the present aralkyl esters of (1',2'-dicarboxyethyl)-undecylenic acid as plasticizers for polyvinyl chloride, these estersare advantageously employed also as plasticizers for copolymers of vinylchloride, for example, the copolymers of vinyl chloride with vinylacetate, vinylidene chloride, methyl methacrylate, acrylonitriie,butadiene, or styrene. Preferably, such copolymers have a high vinylchloride content, i. e.. a vinyl chloride content of at least 70 percent by weight of vinyl chloride and up to 30 per cent by weight of thecopolymerizable monomer.

The plasticized polyvinyl halide compositions of the present inventionhave good thermal stability; however, for many purposes it may beadvantageous to use known stabilizers in the 76 plasticizedcompositions. Inasmuch as the present esters are substantiallyunreactive with the commercially available heat and light stabilizerswhich are commonly employed with polyvinyl chloride or copolymersthereof, the presence of such materials in the plasticized materialsdoes not impair the valuable properties of the present esters. Thepresent esters are of general utility insoftening vinyl chloridepolymers. They may be used as the only plasticizing component in acompounded vinyl chloride polymer or they may be used in conjunctionwith other plasticizers.

What I claim is:

1. A resinous composition comprising a vinyl chloride polymerplasticized with an ester selected from the class consisting oftris-aralkyl (l',2'- dicarboxyethyl)-undecylenates and bis-aralkylmono-alkyl (1',2'-dicarboxyethyl) -undecylenates in which each aralkylradical has from 7 to 8 carbon atoms and each alkyl radical has from 1to 4 carbon atoms.

2. A resinous composition comprising polyvinyl chloride plasticized withan ester selected from the class consisting of tris-aralkyl (1',2'-dicarboxyethyl) -undecylenates and bis-aralkyl monoalkyl(1',2'-dicarboxyethyl)-undecylenates in which each aralkyl radical hasfrom 'I to 8 carbon atoms and each alkyl radical has from 1 to 4 carbonatoms. v

3. A resinous composition comprising polyvinyl chloride plasticized withan ester selected from the class consisting of tris-aralkyl (l',2'-dicarboxyethyDundecylenates and bis-aralkyl mono-alkyl(1,2'-dicarboxyethyl)undecylenates in which each alkyl radical has from1 to 4 carbon atoms and each aralkyl radical has from 7 to 8 carbonatoms, said ester being from to 50 per cent of the weight of thecomposition.

4. A resinous composition comprising a copolymer oi at least 70- percent by weight of vinyl Q chloride and up to 30 per cent by weight oi anunsaturated monomer copolymerizable therewith, said copolymer beingplasticized with an ester selected from the class consisting oftris-aralkyl (1',2' -diearboxyethyl)undecylenates and bisaralkylmono-alkyl (l',2' -dicarboxyethyl)undecylenates in which each aralkylradical has from 7 to 8 carbon atoms and each alkyl radical has from 1to 4 carbon atoms.

5. A resinous composition comprising a copolymer of at least 70 per centby weight of vinyl chloride and up to 30 per cent by weight 01' anunsaturated monomer copolymerizable therewith, said copolymer beingplasticized with an ester selected from the class consisting oftris-aralkyl l',2'-dicarboxyethyl) undecylenates and bis-aralkylmono-alkyl (l',2'-dicarboxyethyllundecylenates in which each alkylradical has from 1 to 4 carbon atoms and each aralkyl radical has from 7to 8 carbon atoms, and said ester being from 5 to per cent of the weightof the composition.

6. A resinous composition comprising polyvinyl chloride. plasticizedwith an ester selected from the class consisting of tribenzyl(1,2'-dicarboxyethyl)undecylenates and dibenzyl monoalkyl (l',2dicarboxyethyl)undecylenates in which each alkyl radical has from 1 to 4carbon atoms, said ester being from 5 to 50 per cent of the weight ofthe composition.

7. A resinous composition comprising polyvinyl chloride plasticized withthe tribenzyl ester of (1',2'dicarboxyethyl)undecylenic acid, said esterbeing from 5 to 50 per cent of the weight of the composition.

JOACHIM DAZZI.

No references cited

1. A RESINOUS COMPOSITION COMPRISING A VINYL CHLORIDE POLYMERPLASTICIZED WITH AN ESTER SELECTED FROM THE CLASS CONSISTING OFTRIS-ARALKYL (1'',2''-DICARBOXYETHYL) -UNDECYLENATES AND BIS-ARALKYLMONO-ALKYL (1'',2''-DICARBOXYETHYL -UNDECYLENATES IN WHICH EACH ARALKYLRADICAL HAS FROM 7 TO 8 CARBON ATOMS AND EACH ALKYL RADICAL HAS FROM 1TO 4 CARBON ATOMS.